Field of the Invention
The present invention relates to a process for producing N-polyoxyalkylated polyamides which are used as a modifier for various fibres and adhesives.
Description of the Prior Art
Polyamide, a kind of synthetic macromolecular compound, has a high melting point, and only a few solvents such as phenols, cresols, some non-protonic and polar solvents and aqueous solutions of a few specific metal salts, can dissolve the polyamides.
Further, the polyoxyalkylation of the polyamide by the reaction with an alkylene oxide without a solvent has been very difficult. On the other hand, if a preferable solvent of the polyamide mentioned above is employed in the reaction to react the polyamide dissolved in the solvent with the alkylene oxide, the alkylene oxide does not react with the polyamide, but reacts preferentially with the solvent.
As a result, there can be found only one prior process (Journal of Polymer Science vol. 15 (1955) page 427) in which a polyamide was reacted in molten form with much excess amount of an alkylene oxide at an elevated temperature higher than the melting point of the polyamide. However, the alkylene oxide is very explosive at such a high temeperature, which is very dangerous. Further, the conversion of the alkylene oxide reacted to the polyamide was less than about 10%, and the resulting polyoxyalkylated polyamide had been colored during the reaction.
Now, the inventors have found a process in which the polyoxyalkylation reaction proceeds smoothly without the dangerous explosion mentioned above, and they have discovered that a polyamide in powder form can be N-polyoxyalkylated with an alkylene oxide in the presence of an alkaline catalyst at a temperature below the melting point of the polyamide when the specified medium is employed in the process.